The number of photo-electrons emitted per second from a metal surface increases when:
1. | The energy of incident photons increases. | 2. | The frequency of incident light increases. |
3. | The wavelength of the incident light increases. | 4. | The intensity of the incident light increases. |
A photon of energy 3.4 eV is incident on a metal having a work function of 2 eV. The maximum K.E. of photo-electrons is equal to:
1. | 1.4 eV | 2. | 1.7 eV |
3. | 5.4 eV | 4. | 6.8 eV |
The spectrum of radiation 1.0 x 1014 Hz is in the infrared region.
The energy of one photon of this in joules will be:
1.
2.
3.
4.
A photocell is receiving light from a source placed at a distance of 1 m. If the same source is placed at a distance of 2 m, then the ejected electron:
1. | moves with one-fourth of energy as that of the initial energy. |
2. | moves with one-fourth of momentum as that of the initial momentum. |
3. | will be half in number. |
4. | will be one-fourth in number. |
The stopping potential for photoelectrons:
1. | does not depend on the frequency of the incident light. |
2. | does not depend upon the nature of the cathode material. |
3. | depends on both the frequency of the incident light and the nature of the cathode material. |
4. | depends upon the intensity of the incident light. |
If in a photoelectric experiment, the wavelength of incident radiation is reduced from 6000 Å to 4000 Å, then:
1. | The stopping potential will decrease. |
2. | The stopping potential will increase. |
3. | The kinetic energy of emitted electrons will decrease. |
4. | The value of the work function will decrease. |
The stopping potential V for photoelectric emission from a metal surface is plotted along the Y-axis and the frequency \(\nu\) of incident light along the X-axis. A straight line is obtained as shown in the figure. Planck's constant is given by:
1. | the slope of the line. |
2. | the product of slope on the line and charge on the electron. |
3. | the product of intercept along the Y-axis and mass of the electron. |
4. | the product of the slope and mass of the electron. |
In an experiment on the photoelectric effect, the frequency f of the incident light is plotted against the stopping potential . The work function of the photoelectric surface is given by:
(e is an electronic charge)
1. | OB × e in eV |
2. | OB in volt |
3. | OA in eV |
4. | The slope of the line AB |
The stopping potential as a function of the frequency of the incident radiation is plotted for two different photoelectric surfaces A and B. The graphs demonstrate that A's work function is:
1. | Greater than that of B. | 2. | Smaller than that of B. |
3. | Equal to that of B. | 4. | No inference can be drawn about their work functions from the given graphs. |
The graph between the intensity of light falling on a metallic plate (I) and the generated current (i) is given by:
1. | 2. | ||
3. | 4. |